Low back pain is a significant public health problem that has reached epidemic proportions. It is the most expensive musculoskeletal disorder and represents the largest category of medical claims. It is also one of the major reasons reported for using Complementary and Alternative Medicine. The long-term objective of this proposal is to evaluate the efficacy of lyenger yoga therapy on chronic low back pain (CLBP) in a large scale clinical trial. This objective will be achieved through the following specific aims: 1) Determining the methodology best suited for evaluating the efficacy of lyengar yoga therapy on CLBP. The most efficient recruitments strategy, optimal length of yoga therapy, safety, appropriate outcomes, compliance and attrition rates will be investigated; 2) Evaluating the effectiveness of lyengar yoga therapy for decreasing pain-related outcomes including functional disability, pain intensity, and pain medication usage, and 3) Evaluating the effectiveness of lyengar yoga therapy for decreasing medical utilization by tracking the numbers of medical visits, number of procedures, number and type of medication, and converting them to resource value units and costs. Patients with PEIA and HealthPlan insurance and a diagnosis of CLBP will be recruited through self referral and referral from health professionals. Patients will be screened by study physicians to determine their eligibility based on study inclusion and exclusion criteria. After the baseline assessment, subjects will be randomized into one of two groups, a wait list control receiving standard medical care and yoga therapy. The yoga therapy intervention will contain up to 24 weeks of biweekly classes. Changes in pain-related outcomes, medical utilization and compliance will be assessed after 12 and 24 weeks to determine the amount of yoga therapy necessary for clinically significant differences between groups. The primary outcome of the study is functional disability. Secondary outcomes include pain intensity, pain medication usage, and medical utilization. Subjects will be evaluated using the Oswestry Disability Questionnaire, the Visual Analog Scale, a pain medication usage questionnaire and medical claims data. We anticipate that subjects who complete the yoga therapy intervention will report less functional disability, a reduction in pain intensity, usage of pain medication and medical utilization compared to the wait list control receiving standard medical care.